Waves
Lesson #5: Sound and Communication (2-part lesson)
Time Frame: 60 minutes for each part
Please write the vocabulary on the board before each lesson.
Lesson #5, Part 1 should be taught as an extension lesson by the classroom
teacher before Lesson #5, Part 2.
Video suggestion for code/communication (to be used during ELA block) :
PBS Specials, True Whispers: The Story of the Navajo Code Talkers
Learning Standards:
Science
Waves and their Applications in Technologies for Information Transfer
1) Generate and compare multiple solutions that use patterns to transfer information.
2) Digitized information can be transmitted over long distances without significant
degradation. High-tech devices, such as computers or cellphones, can receive
and decode information--convert it from digitized form to voice-- and vice versa.
Crosscutting Concepts
1) Knowledge of relevant scientific concepts and research findings is important in
engineering.
2) Engineers improve existing technologies or develop new ones.
3) Science affects everyday life.
Engineering
Engineering Design
1) Plan and carry out fair tests in which variables are controlled and failure points are
considered to identify aspects of a model or prototype that can be improved.
2) Plan and conduct an investigation collaboratively to produce data to serve as the
basis for evidence, using fair tests in which variables are controlled and the
number of trials considered.
3) Testing a solution involves investigating how well it performs under a range of
likely conditions.
4) At whatever stage, communicating with peers about proposed solutions is an
important part of the design process, and shared ideas can lead to improved
designs.
English / Language Arts
1) Explain events, procedures, ideas, or concepts in a historical, scientific, or
technical text, including what happened and why, based on specific information in
the text.
Student will be able to:
1) Decode and write messages in Morse code.
2) Gain an understanding of communication technology.
3) Describe the difference between independent and dependent variables.
4) Explain how a string phone works.
Resources and Materials:
Item
Science Journals
Part 1:
“A History of Communication Technology: Inventing the
Telegraph and Morse Code” pamphlet
Morse code worksheet
Part 2:
3 types of cups: paper, plastic, and Styrofoam
3 types of string: fishing line, yarn, and twine
Paper clips
String Phone experiment worksheet and datasheet
String Phone experiment station instructions
Rulers
Scissors
Amount
50 (in bin)
25 (in bin)
1 box of each (in bin)
1 spool of each (in bin)
1 box (in bin)
25 (in bin)
9 (in bin)
1 per group (in classroom)
1 per group (in classroom)
Lesson 5 Part 1: Morse Code
This lesson should be taught as an extension lesson by the classroom teacher
before Lesson #5, Part 2.
Focus Activity: Ask students to think about and write about the following questions in
their science journals: How can you send a secret message from one side of the room
to your friend who is on the other side of the room? What if your friend is in the room
next door?
Introduction: Read the pamphlet “A History of Communication Technology: Inventing
the Telegraph and Morse Code” with your class. Tell them that they will be learning
more about how to use Morse code. Show students a video to demonstrate what the
clicking of a telegraph sounds like: http://www.youtube.com/watch?v=_J8YcQETyTw
Activity:
1) Have students work on the Morse code worksheet. They will decode words and a
sentence in Morse code using the Morse code alphabet provided on the
worksheet.
2) Have students pair up to compose their own written Morse code messages. Ask
students to create a message in Morse code about their favorite part of science
class. Then have them swap messages with their partner and decode their
partner’s hidden message. They should write down whatever they think the
message is using the regular English alphabet in their science journals.
3) Challenge Game (as time allows): Have students work in groups of 4-5.
Students have to be very quiet for this part of the activity to work! Recall that
sound waves can travel through solid mediums, such as a desk. Tell students
they will be passing a Morse code message through the desk to the other
students in their group. Have students take turns tapping a five letter word on
their desk. As one student taps out the message on the desk, the other students
should put their ear on the desk to listen for the sound. The student tapping the
message should tap slowly to ensure that their group members receive the
message. Group members should record each letter as soon as they figure it out
and hole up a thumbs up signal to allow the student tapping the message to
continue on to the next letter.
4) Challenge Game (as time allows): Play telephone with Morse code. The student
or teacher who starts each line picks a letter and sounds it out in Morse code to
the next person (i.e. say “dot dot dot” to signal the letter “S”), who passes the
sounds on and so on until the last person, who must decode the letter and say
the letter out loud. You can also split the class into two or more lines and
compete to see which letters have the fastest and most accurate Morse code
counterparts.
Closure: Students should answer the following questions in their science journals:
According to the article we read, why was the invention of the telegraph so important?
How does Morse code allow us to send messages? Why do you think we don’t use
Morse code today? What other forms of technology do we use?
Part 2: String Phone experiment
Focus Activity: While you are setting up, write on the board the question, "What are
the steps of the scientific method?" and give students a few minutes to respond in their
science journals. Review the scientific method with students. Explain the following
steps: identify a problem, make a hypothesis, test your hypothesis, collect data, and
make a conclusion (was the hypothesis right or wrong). Discuss why each step in the
scientific method is important to a scientist.
Introduction:
1) Introduce the string phone as the solution to the model problem. Demonstrate
how to make a string phone. Explain the steps to the students as you’re doing
the demonstration. Poke a hole into the bottoms of the cups using a pencil or
push pin. Thread the string through the hole in one of the cups. Tie a paper clip
onto the end of the string and knot it in place inside the cup, so that the paper
clip is inside the cup and the rest of the string extends through the hole in the
bottom of the cup. Repeat for the cup on the other side of the string.
2) Introduce students to the idea of variables by contrasting this string phone with
another string phone (made during prep time) that is made with a different type
of string and cup and a longer or shorter length of string. Ask students how the
two are different. Summarize variable as a characteristic attribute, or quality, of
the way the string phone is made or used that can be changed.
Activity:
1) Tell students the problem they will be trying to solve for today: what materials
can you use to make the optimal string phone, one that will send the clearest
and loudest message without leaking the sound to others. (Feel free to write this
on the board to keep up during the lesson as a reminder). Suggest that there are
bonus challenges they can try if there is time lefts, such as using a blindfold,
trying a string phone that will go all the way down a long hallway, or going
through a door or other obstacle. They will be experimenting with variables used
to make string phones in order to solve the problem. Explain that if you change
more than one variable at a time, you won't know exactly which change had
what effect. So you should only change one variable at a time, and keep the
other ones constant. The one that they change is called the experimental
variable, and the ones they keep constant are the control variables. Explain also
that they should test each experimental variable under 2 different conditions (i.e.
long vs. short string length, twine vs. fishing line string type, or styrofoam vs.
plastic cup), so that they have something to compare for each of the 3 conditions.
For each condition, the students should do 3 trials, or tests, to make sure
nothing coincidental happened.
2) Students will work at 3 stations, one for each of the 3 standard experimental
variables. In each group, one student will tell the message through the phone, a
second will listen through the phone, and a third will try to hear the message by
standing next to them. They will make all the string phones for the station where
they begin and then reuse the phones at each subsequent station they rotate to.
Groups should be about 3-4 students, so feel free to double up at each station.
3) Students should take turns making the phones, testing the phones, and
recording the experimental information in their science journals. Have students
use the template from the student directions worksheet. Each group should
decide which 2 of the 4 phones at each station they should use (or the 2 specific
lengths of string they will use at the station for length of string) together, in
coordination with any other groups sharing their station. They should circle the
better condition in each experiment.
4) If time permits, ask students to think of another variable they could test (i.e. the
size of the cup or the presence of an obstacle or not or assymmetrical cups) and
have them devise an experiment. They should have their idea checked by a
teacher before attempting. Experiment with challenges, such as using a blindfold,
trying a string phone that will go all the way down a long hallway, or going
through a door or other obstacle.
Closure: Which materials worked to make a string phone? What does this tell you
about how sound waves travel through solids?
Assessment: Science journal responses, participation in activity, and experiment
sheet.
Name: _________________________________________________
Date: _____________________
Morse Code
Morse code is one way of sending messages quickly from far away. Using the chart
above, you can spell out something you’d like to say in the morse code alphabet. For
example, in morse code CAT would be C −  −  / A  − / T −.
Now try decoding these words on your own:
1)    / − − − /   
__________________________________________
3)   −  / − − − / − − − / −  
__________________________________________
5)    / − − − /   − / −  / −  
__________________________________________
7)  −   /   − / −  / −  −  /    
__________________________________________
2) − /     /   /   
_______________________________________
4)    / − / − − − /  − − 
_______________________________________
6) −  −  /  −  /  /    / −
_______________________________________
8)  − − /  − /    − /  /   
_______________________________________
9) − /  −  / − − − /   − / − −  /    
___________________________________________________________________________________
10)    /   − / −  −  / −  −  /  /    /   
___________________________________________________________________________________
Great! Now try decoding this sentence:

/−−−/−−/
−−−/−−−/−

/−/−−−/−−−/−−−
−//−/−/−//−/−−

 − / −    / − − − /  − / −
   / −  −  /   /  / −  / −  −  / 

______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Now you’re ready to try writing your own message! Try sending a message to a friend.
Station #1
Experimental variable: String length
Procedure:
1) Find out the length of string that sends the loudest and
clearest message through a string phone.
2) Complete 3 trials with each length of string.
3) Record your observations in your science journals.
4) Circle the best condition in your journal, or write it at the
bottom of your observations.
Station #2
Experimental variable: String type
Procedure:
1) Find out the type of string that sends out the loudest and
clearest message through a string phone.
2) Complete 3 trials with each beak, burying the worms
after each trial.
3) Record your observations in your science journals.
4) Circle the best condition in your journal, or write it at the
bottom of your observations.
Station #3
Experimental variable: Cup type
Procedure:
1) Find out the type of cup that sends the loudest and
clearest message through a string phone.
2) Complete 3 trials with each beak.
3) Record your observations in your science journals.
4) Circle the best condition in your journal, or write it at the
bottom of your observations.
Name: _______________________________________
Date: _________________
String Phone Experiment Directions
Vocabulary
Variable: something about the string phone that you can change, like the materials
you use
Control variable: variables that you keep the same in each experiment
Experimental variable: one variable that you change in each experiment
Condition: two different possibilities for each experimental variable
Trial: a test
Directions to make a basic string phone:
1) Poke a hole into the bottoms of the cups using a pencil or push pin.
2) Thread a piece of string through the hole in one of the cups.
3) Tie a paper clip onto the end of the string and knot it. The paper clip should be
inside the cup and the rest of the string should go through the bottom of the cup.
4) Repeat for the cup on the other side of the string.
Your Mission: To make the best string phone. This string phone should send a loud
and clear message, but it should not reveal what you're saying to other people nearby.
Task:

Work together to test 2 phones at each station. For the first station only, you will
be making the phones. For the following stations, you will test the phones that
your classmates have made.

Record the variables in your experiment and your results for each trial, like in the
example below.

Circle the condition in each experiment that was better.
Example Record:
Experiment #___1___:
Experimental variable: length of string
Control variable (fill in information only for the variables you plan to keep the same):
Length of string: ________________________
Type of string: _fishing line_______________
Type of cup: _plastic cups________________
Condition #1: ___short string - 12 inches__________________
Trial #1 results:
I said "I think this is working." My partner thought the sound was ok. Our
other partner did not hear what we said.
Trial #2 results:
I said "how about this time?" My partner could hear what I said pretty well.
Our other partner did not hear what we said.
Trial #3 results:
I said "this is the last trial." My partner said "yes, it is the last trial." Our
other partner did not hear what we said.
Condition #2: ___long string - 36 inches__________________
Trial #1 results:
My partner said "did you see that show on tv?" But the sound was too quiet
and I couldn't really hear. Our other partner did not hear what we said.
Trial #2 results:
This time my partner was louder, so I hear the message, which was "there's
a bug in your hair!" It was loud, so our other partner could hear what we said.
Trial #3 results:
My partner said "how many eggs do you have?" But I thought the message
was "Herman yikes doof ave?" Our partner could not hear what we said.
Conclusion:
The shorter string was better because it was clearer, louder, and no one else
heard what we said.
Challenge: If you finish early or your teacher says there is enough time, try to think of
another variable you could change. Which 2 conditions could you test for this variable?
Try one of the bonus challenges, such as making a string phone that can go through
doors, using blindfolds, or making a really long string phone that goes down the entire
hallway. Check with your teacher before you try.
Data Sheet
Experiment #________:
Experimental variable:
Control variable (fill in information only for the variables you plan to keep
the same):
Length of string: ________________________
Type of string: __________________________
Type of cup: ____________________________
Condition #1: _______________________________________
Trial #1 results:
Trial #2 results:
Trial #3 results:
Condition #2: _______________________________________
Trial #1 results:
Trial #2 results:
Trial #3 results:
Conclusion: